Repairing a P4400 Kill A Watt meter (aka 1800-Watt meter)

Recognize this thing? It measures your power usage and is somehow always more expensive than you expect. I definitely blew a fuse or something in mine drawing a lot of power - time to fix it!

P4400 Kill A Watt power usage meter

I learn after the fact that this is only designed to handle 15 amps, which at 120 volts is 1800 watts! That's a lot of watts.

Anyways, let's take it apart! At first glance it looks like something shorted on the male plug side of the board, but it turns out that part is fine. Seems like quite a lot of solder, but

Male plug, with lots of solder!

I find the fuse, and unfortunately it isn't replaceable. Using a multimeter, I see that there is no current across the fuse. Time to take it off!

Female plug and fuse

Female plug part of the circuit and the fuse

No current!

Multimeter checking the current across the fuse, showing that the fuse is blown

Snip snip!

Wire cutters removing the bad fuse

So how do we add a new fuse? It turns out there are two really handy test contacts that are perfect for soldering! I have a spare car fuse from a previous project so I can use that.

Easy solder points!

Spare car fuse - hopefully not too big

First solder

Second solder

And that's it! I'm barely able to fit the fuse in, but with a little poking and prodding I'm able to jam it all in there. I plug it in and it works! Hooray!

Barely fits

It works!

Hopefully this helps you repair your kill-a-watt meter if it breaks :)

Published: 2021-02-01